It's a year today since 298 people died when Malaysia Airlines Flight MH17 was shot down over eastern Ukraine.
We know exactly what happened to that plane and the people on board, but what became of Malaysia Airlines flight MH370 is still a complete mystery.
It disappeared on March 8, 2014 after leaving from Kuala Lumpur, and has sparked the most extensive aviation search in history.
Aviation expert Geoffrey Thomas, who has been watching the search efforts unfold, says when you consider the magnitude of the area searchers are looking at, it's no wonder they're taking so long.
"We are eliminating areas where it [MH370] is not. They're searching an area which is about 1800 kilometres southwest of Perth, and the area they're searching is about 120,000 square kilometres. They've roughly done half of it," he said on TV3's Paul Henry programme this morning.
Mr Thomas says it is likely the search will last into early next year.
So far searchers have found no trace of the missing aircraft, including any debris. Mr Thomas however, remains confident they're are looking in the right area.
"I've listened to all the theories, and I have analysed many of them, and some of the theories work fine in isolation… the fact that it flew on for seven hours, and sent the tracking information that we have indicates to me conclusively that it is in the Southern Indian Ocean," he says.
Although, Mr Thomas says he has no idea why it the plane was over that stretch of water in the first place.
"It has to be human factors […] there are too many things that we know for certain that have happened to that airplane, that can't be an accident. It has to be deliberate. "